JSyn - modular synthesis API for Java.
JMSL - Java Music Specification Language
PortAudio - cross platform audio I/O API for 'C'

Audio Examples made using JSyn - a Java Synthesizer API

Envelope Editor

How it works:

An envelope contains an array of {duration,value} pairs called frames. In this example the contour described by these shapes is used to control the amplitude of an oscillator.

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